This invention relates to a device and method for use in a downhole oil and gas recovery operation to measure and record the setting motion of packers.
Downhole sealing devices, such as packers, bridge plugs, and the like, are commonly used in many oilfield applications for the purpose of sealing against the flow of fluid to isolate one or more portions of a wellbore for the purposes of testing, treating or producing the well. For example, a packer is usually suspended from a tubing string, or the like, in the wellbore, or in a casing in the wellbore, and includes one or more elastomer elements which are activated, or set, so that the packer elements are forced against the inner surface of the wellbore, or casing, and compressed to seal against the flow of fluid and therefore to permit isolation of certain zones in the well.
When setting sealing devices of this type downhole, a sequence of events occur that generally include the shearing of pins, the movement of components, the compressing of elastomers, the expansion of a slip and the deformation of back-up shoes. It is important to maintain this sequence in a fairly precise manner to obtain a proper set despite the fact that the sequence can be adversely affected by several parameters including bottomhole pressure, bottomhole temperature, stroke time and distance, and external forces.
Also, after a packer has been set, it may move or leak. The cause of the moving or leaking is usually difficult to determine due to a lack of knowledge of the above parameters and other parameters such as the time required to complete the set, the setting force imparted to the packer, etc.
However, it is difficult to measure and quantify these parameters and adjust them as necessary to ensure that the correct sequence is maintained and/or the moving or leaking of the device is eliminated.
Therefore, what is needed is a system that measures, quantifies and records the above parameters to enable the correct sequence to be maintained and/or the cause of any moving or leaking of the sealing device to be determined.